Double magnet snap action



Nov. 17, 1942.. R. PENN 2,302,250

l DQUBLE MAGNET SNAP ACTI-ON Filed May 7. 1941 4f 45 WFH/46 @we/2id? Fa/v 976/3 22 Patented Nov. 17, 1942 DOUBLE MAGNET SNAP ACTION Ralph Penn, St. Louis, Mo., assigncrto Penn Electric Switch Co., Goshen, Ind., a corporation of Iowa Application vray 7, 1941, serial No. 392,316

(o1. zoo-s3) 9 Claims.

My present invention relates to a double magnet snap action structure particularly designed for automatic control switches and the like.

One object of the invention is to provide a structure of this character which is simple, durable and comparatively inexpensive to manufacture.

Another object of my invention is to provide a switch structure in which a magnet is used for giving snap action to a switch arm, the switch arm being characterized by having an armature and the magnet by having a yoke with the armature movable between the arms of the yoke from a position adjacent one arm to a position adjacent the other arm.

Still another Object is to provide a yoke on a magnet so cooperating with an armature that` snap action is secured in both directions of movement of the armature, both by reason of the armature receding from one arm of the yoke and approaching the other arm.

A further object is to provide a double magnet snap action mechanism particularly adaptable for switch or other control structures wherein a lost motion connection is provided between an actuating elem-ent, such as a bellows operated arm, and a switch arm or the like.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my device whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawing.' Although the invention is susceptible of a variety of embodiments, it is unnecessary to fully describe and illustrate more than one in order to give a full understanding of the invention both from its structural and` functional standpoints. Accordingly, I have illustrated a preferred and desirable embodiment of the invention in the accompanying drawing, in

which:

Figure 1 is an elevation of a switch structure including my double magnet snap action mecha-V double magnet l and armature elements of my snap action mechanism. A l

On the accompanying drawing, I have used the in the casing III a bell crank I2 is -pivoted at I4. The bell crank may be automatically controlled by any suitable pressure or temperature actuated mechanism. By way of example, I show a pressure bellows I5 within a bellows housing I6 and operatively connected with the bell crank I2 by a stem Il. A range spring I8 and an adjusting screw I9 therefor are connected with the bell crank I2 to retain it in engagement with the stem Il.

A switch arm 20 is controlled by the bell crank I2 through a leaf spring 2|, rods 22 and 23 and flanges 24 and 25 fori ed on the switch arm 20. Th-e switch arm 20 and its flanges 24 and 25 are pivoted as at 26 to a bracket 2l. The bracket in turn is supported bya bar 28 of insulating material in the casing I0.

The switch arm 20 carries contacts 29 and 30, the contact 30 being connected by a leaf spring 3I and the rivets 32 to the switch arm, with the contact 30 extending loosely through an opening in the switch arm. The contacts '29 and 30 are adapted to coact with contacts 33 and 34 mounted on a bracket 35. The brackets 2l and 35 may be electrically connected with terminal screws 36 and 31.

-For providing snap action in both directions for the switch arm 20, I provid-e a pair of armature portions 38 and 39 thereon adapted to coact with yokes 40 and 4 I. The yoke 40 is permanently magnetized so that its arms are both north polarity, for instance, by being attached to the north pole of a horseshoe magnet I42. Similarly, both arms of the yoke 4I are of south polarity by attachment of the yoke to the south pole of the magnet 42. The magnet in turn may be supported on a bracket 43, as by screws 44.

The contacts 29 and 33 limit the movement of the switch arm in one direction, and a stop secured to the casing I0 by a screw 46 limits its movement in the opposite direction. The degree of movement is such that the armatures 38 and 38 are adjacent the lower arms of the yokes 40 and 4I in the closed switch position of Figure 1,

and adjacent the upper arms of the yokes in the switch-open position of Figure 2.

The means of connection between the rod 23 and vthe switch arm. 20 is by means of a right angle'end 41 on the rod 23 constituting a pin coacting with a slot 4'8 in the flange 24 of the switch arm 20. Thus when the rod 23 is moved downwardly from the position of Figure 2, the pin 4l will first engage the bottom of the slot 48 and energy will be accumulated in the bellows reference numerallll to indicate a casing. With- 52 and in the leaf spring 2|, until such energy is sumcient to overcome the attraction of the upper arms of the yokes 40 and 4I on the armature portions 38 and 39. The switch arm 2U will then be moved downwardly by the built-up energy referred to, and the armatures 38 and 39 will recede from the upper arms of the yokes 40 and 4|, whereby their attraction effect thereon is diminished. At the same time, the attraction effect of the lower arms of the yokes is increased whereby the snap action effect is augmented.

I am aware that heretofore a double armature arrangement with the two armatures spaced on opposite sides of the pole of a magnet has been patented in the Persons Patent No. 2,030,933, and that the Hoeschen Patent No. 1,477,350, shows an armature moving between two poles of a magnet so as to approach one as it leaves the other. My structure differs from the Hoeschen arrangement in that the armature, such as 38, always remains of the same polarity, such as south, as it moves between the two arms of the yoke 40 which are both north polarity. Therefore, at no time does the armature have to change its polarity, and the hesitation experienced by the Hoeschen arrangement when the armature is midway between the two magnetic poles is entirely eliminated with my structure. My structure also involves less 'mass in the switch arm and armatures than required in the Persons arrangement, so that the switch can operate between closer limits and with more assurance of no bouncing of the contacts.

When the switch moves from the closed position of Figure 1 to the open position of Figure 2, the pin 4l first contacts the upper end of the slot 48 and then, after energy is accumulated in the bellows I5 and the spring 2l to a point sufficient to move the switch arm, the armatures 38 and 30 recede from the iield of the lower arms of the yokes 40 and 4| and approach the iields of the upper arms. All of the yoke arms in this operation cooperate to eiect a full throw of the switch arm from one limit of its movement to the other after it is once started, and the switch arm can' overrun the movement of the pin 41, due to the elongation of the slot 48.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to pole of said magnet, a single armature carried by said operating arm and located between the arms or' said yoke whereby magnetic lines of force pass through said armature from one of said arms to the other and in ali positions of the armature between the yokes retains the armature magnetized at the same polarity, seid operating arm being limited in movement to s armature in one position adjacent one of said arms of said yoke, and in its other position adjacent the other arm of the yoke.

2. In a switch for controlling an electric circuit, a magnet, an operating arm movably mounted, a yoke mounted on a pole o said magan armature carried by said operating arm located between the arms of said yoke wherety magnetic lines of force continuously pass through said armature from one of said arms to the other and in all positions of the armature between the yokes retains the armature Vmagnetized at the same polarity, said operating arm being limited in movement with its armature in one position being adjacent one of said arms of said yoke, and in its other position being adjacent the other arm of the yoke, and contacts operated by said operating arm to assume closed position when the arm is at one of its limits of movement.

3. In a switch structure, a two pole magnet, a switch arm, a pair of armatures on said switch arm, a yoke o n each pole of said magnet, said armatures being located between the arms of said yokes and each in the magnetic field of its respective yoke, said switch arm beingmovable through a range with said armatures adjacent one arm of each yoke at one limit of movement of the switch arm and the armatures adjacent the other arms of said yokes at the other limit of movement ofA the switch arm, switch contacts engaged and separated by said switch arm when at opposite limits of its movement, and an actuating device connected by a lost motion connection with said switch arm.

4. In a switch structure, a two pole magnet, a switch arm, a pair of armatures on said switch arm, a yoke on each pole of said magnet, said armatures being located between the arms of said yokes and each in the magnetic field oi its respective yoke, said switch arm being movable through a range with said armatures adjacent one arm of each yoke at one limit of movement of the switch arm and the armatures adjacent the other arms of said yokes at the other limit of movement of the switch arm, switch contacts engaged and separated by said switch arm when at opposite limits of its movement, and an actuating device connected by a resilient connection with said switch arm.

5. In a switch structure, a two pole magnet, a switch arm, a pair of armatures on said switch arm, a yoke on each pole of said magnet, said armatures being located between the arms of said yokes and each in the magnetic field of its respective yoke, sad switch arm being movable through a range with said armatures adjacent one arm of each yoke at one limit of movement of the switch arm and the armatures adjacent the other arms of said yokes at the other limit of movement of the switch arm, and an actuating device connected by resilient and lost motion connections with said switch arm.

6. In a switch structure, a two-pole magnet, a switch arm, a pair of armatures on said switch arm, a yoke carried by each pole of said magnet and each having one of said armatures located between the arms thereof, said switch arm being movable through a range with said armatures adjacent one arm of each yoke and with the armatures adjacent the other arm of each yoke at opposte limits of movement of the switch arm, and switch contacts controlled by said switch arm.

,'7. A double magnet snap acting structure comprising a control arm, an armature carried thereby, a magnet having a pair of poles and a yoke secured to each pole thereof whereby the two arms of one yoke are permanently magnetized at one polarity and the two arms of the other yoke are permanently magneti/ssd at the opposite polarity, said armature being arranged with. a portion to move between the arms of one yoke and another portion to move between the arms of 'the other yoke whereby movement of said arto move an additional distance over and above matures in one direction causes said portions to snap from one position adjacent one arm of each yoke to an opposite position adjacent the other arm of each yoke, and an actuator for said control arm.

8. A. double magnet snap acting structure comprising a control arm, an armature carried thereby, a magnet having a yoke secured to a pole thereof whereby the two arms of the yoke are permanently magnetized at one polarity, said armature being arranged to move between said arms of said yoke whereby movement of the armature in one direction causes it to snap from a position adjacent one arm of said yoke to an opposite position adjacent the other arm of the yoke, an actuator for said control arm, and a lost motion connection between said actuator and vsaid control arm to permit the control arm that imparted to it by the actuator after the actuator initially moves the control arm. A

9. A double magnet snap acting structure comprising a control arm, an armature carried thereby, a magnet having'a yoke secured to a pole thereof whereby the two arms of the yoke are permanently magnetized at one polarity, said armature being arranged to move between said arms of said yoke whereby movement of the armature in one direction causes it to snap from a position adjacent one arm of said yoke to an opposite position adjacent the other arm of the yoke, and an actuator for said control arm having connection therewith in which energy may be built up to initiate movement Aof said armature from one limit of its movement to the other.

RALPH PENN. 

